Douglass Elementary
BVS3D
3D Symmetry Lesson
Date: 6/4/10
Grade Level: 4th Grade
Length of Lesson: 2-3 hours
Standards(s) Addressed:
BVSD Mathematics Standard 4: Students use geometric concepts, properties, and
relationships in one, two, and three dimensions to model and solve problems. They
communicate their reasoning used to solve these problems.
Correlation to NTCM Standards - Geometry: Apply transformations and use symmetry to
analyze mathematical situations.
Grades 3-5 Expectations:
o Identify and describe line and rotational symmetry in two- and threedimensional shapes and designs.
o Build and draw geometric objects
o Recognize geometric ideas and relationships and apply them to other
disciplines and to problems that arise in the classroom or in everyday life.
Smart Goal:
To have 80% of the students understand that a line of symmetry divides a figure into two
congruent parts with 80% proficiency.
Lesson Objectives Addressed:
Identify and make symmetrical figures, and draw a line (or lines) of symmetry.
Materials:
3D Projector
3D Glasses – class set
Classroom3 – Symmetry Simulation
White Board and Markers
Ruler and Grid Paper for Assessments
Pattern Blocks
Hand Mirrors
Geo-boards
Colored Rubberbands
Vis-à-vis Markers
©2010 Created by Lynn Twietmeyer, Dawne Mangus, and Holly Colangelo
1
Douglass Elementary
BVS3D
Acetate sheets to draw on with Vis-à-vis markers (put these sheets over the
handouts to save paper)
Paper Towels to clean off acetate sheets
Symmetrical shape packet (double-sided)
o 3 pages of different symmetrical, geometric shapes (one
shape on each page)
o 1 page is grid paper which has a half of a symmetrical,
geometric shape (to use with the hand mirror). We will
use this polygon to the right
Scott Foresman Mathematics, Grade 4, Vol 3, Ch 8, Lesson 7
Pre-Assessment:
Hand out a sheet of grid paper with a symmetrical, geometric shape and a ruler:
Ask students how many lines of symmetry the shape has
Ask them to draw the line(s)
Give them several pairs of congruent figures:
Ask the students to determine whether or not the figures are related by flip, slide, or
turn
Opening:
Discuss and define straight lines and curved lines
What is symmetry?
o The property of exact balance in a figure; having the same size and shape
across a dividing line.
o “If half a figure can be matched to the other half by folding, then the figure is
symmetric.” – Scott Foresman, 8-7
Go over the definitions of:
o Congruent – the same size and shape
o Symmetric – can be folded into two congruent halves
 Line of Symmetry – fold line, bilateral
Lesson Part One – Line of Symmetry – Day 1:
Start up the 3D simulation – have the flower image projected onto a white board
Ask the questions:
o Is there a line of symmetry?
o Where is the line of symmetry?
o How many lines of symmetry are there?
Kids interactively utilize the white board to draw what they think are the lines of
symmetry (they come up and draw their lines)
Handout the symmetrical, geometric shapes packet, Geo-boards, and rubberbands
(discuss safety first)
©2010 Created by Lynn Twietmeyer, Dawne Mangus, and Holly Colangelo
2
Douglass Elementary
BVS3D
Have students create the shapes on the first two pages of the packet with one color
of rubberband and add the lines of symmetry with another color (teacher can
observe those that are having difficulty with the task)
o Students can work with a partner after they have completed one shape on
their own
Have the students create a new shape(s) with lines of symmetry
o This will determine whether or not the student can generalize and transfer
learned information
Re-collect the packet when done to use tomorrow
Lesson Part One – Line of Symmetry – Day 2:
Have a new shape projected on the white board with the document camera. Ask
questions to re-emphasize:
o Is there a line of symmetry?
o Where is the line of symmetry?
o How many lines of symmetry are there?
Kids interactively utilize the white board to draw what they think are the lines of
symmetry (they come up and draw their lines) – recapitulate former lesson
Pass out the clear acetate sheets, the geometric shape packet, vis-à-vis markers, and
hand mirrors
Students use pages 1-3 of the shape packet to draw lines of symmetry on the acetate
sheet for each shape
o Complete the last page using a mirror image (draw the rest of the image
using the mirror)
 In addition, for those tactile learners, provide pattern blocks to place
on the grid paper to complete the shape. This is an excellent form of
in-class differentiation.
Lesson Part Two – Turn Symmetry – Day 3:
Proceed to Strategy One in the 3D Simulation
o Choose one of the shapes to be projected on the white board
Ask the students - How many lines of symmetry?
Go through the turn symmetry using the simulation
o Choose the square first, go through the turn symmetry, and then choose
another shape to show the difference in shapes
Teacher will then take pattern blocks and demonstrate the flip and slide actions
utilizing a document camera (so that all the students can see)
Pass out pattern blocks and have the students demonstrate with a neighbor, or in
small groups:
o Flip
o Slide
©2010 Created by Lynn Twietmeyer, Dawne Mangus, and Holly Colangelo
3
Douglass Elementary
BVS3D
Differentiation (out of class):
TAG students will work with the TAG coordinator and complete Strategy 2 of the 3D
simulation. They will create their own fold and punch activities and challenge other
students within their small group.
Closing:
For follow-up, review, or additional practice, visit the following website:
http://www.innovationslearning.co.uk/subjects/maths/activities/year3/symmetry/shapeGame.swf
Homework:
o Have the students find something in nature that is symmetrical
 They can use the playground, home, etc.
 Draw it or bring it in to discuss with the class (depends on size)
Connection to Literature:
Accidents May Happen: Fifty Inventions Discovered by Mistake by Charlotte Foltz Jones talks
about how the kite was invented. Great real-life connection to the kite and a discussion on
how many lines of symmetry a traditional kite has.
Teacher Reflection: to be done after lesson
Post-Assessment:
Hand out a sheet of grid paper with a symmetrical, geometric shape and a ruler:
Ask the students how many lines of symmetry the shape has
Ask them to draw the line(s)
Give them several pairs of congruent figures:
Ask the students to determine whether or not the figures are related by flip, slide, or
turn
Retention Assessment (6-8 weeks later):
Assess the students again to see if 80% are retaining 80% or more of the information they
learned earlier in the year. To do so:
Repeat Post-Test Assessment
On the back of the grid paper, have the students draw a shape of their own with 3
lines of symmetry
o This will determine whether or not the student can generalize and transfer
learned information
©2010 Created by Lynn Twietmeyer, Dawne Mangus, and Holly Colangelo
4